Like so many of these posts, this is prompted by my being asked similar questions by many of our lovely customers. So here's my thoughts on whether new frames should be an option for you and what might be available.
Should I, shouldn't I?
My basic advice is only consider new frames if;
your existing frames are missing metal (or badly damaged)
you are swapping from frameless to framed
you are undertaking a complete refurbishment (of all deck hardware)
you just won the lottery (goes with the one above)
Older boats (ie <2005) have a patina which permeates through all the deck hardware and rig. Those aluminium fittings show a few scrapes and are slightly duller than when spanky new. This patina is in keeping with the experiences shared, the storms weathered and the bleaching from UV. In a nutshell the look is both consistent and in keeping with the old girl.
So if you introduce some spanky new frames amongst this hard earned patina will the new fit with the old? No. I could go on, but if anything the new will make what before was a lovely patina look just plain knackered. At this point you will face the predictable dilemma concerning shall we replace the lot (option 3 above) to bring back consistency?
Now clearly, if the frames are beyond redemption (ie missing metal or being changed in format) then this is the pill you have to swallow. But if not, it's worth standing on your deck and trying to imagine the impact of new on old and making a considered decision with your eyes opened.
Options for new frames - the inverse rule
Frame builder (like the one we use) are a risk averse lot. They will only use sections they have clear title to and won't even consider using a wholesaler section without. Also, as they typically have to buy half a tonne at a time they tend to hold very few section variants.
So the smaller frame builders (like ours) often have one section, probably in single and twin channel variants. As the business size increases, so does the number of sections, though you're never talking many. Forget comparing this with buying kitchen tiles at B&Q (other suppliers are available), where many (too) many versions are available. No, in the frame world more than one is a lot.
Now for the inverse rule (I appreciate you've on tender hooks at this point). If you want a few frames made, the small frame builders are you friend, but the larger companies (eg Seaglaze, Trend) are sadly not. Their focus is yacht builders who want 50 sets or mega yacht clients whose wallet is larger than your boat. So, those that have more choice are not interested and those that are have one section. The point I'm trying to labour is that choice is VERY limited.
Now, if you have a Westerly, Sadler or even perhaps a Moody etc then the sections we can access are a good fit. Basic in design, they are intended for external fasteners (typically M4 raised slotted SS machine screws) and an internal clamping ring (20mm wide 1/8" (~3.2mm) bar bent to follow the outside of the cutout/frame) fitted with interscrew bushes. This nut and bolt type approach clamps the frame to the hull and provides a pleasing look on the inside.
If your frame is one which clamps from the inside, eg Moonlight, where the fasteners are on the inside and screw into the outer frame (so the outer frame face has no screws showing) then few options exist (Technautic does some of these but they tend to be quite a heavy section). Companies like Gebo (NL) will undertake bespoke work (and are excellent quality) but the price and lead time will have you sitting down tout suite. Similarly if you have an older boat (eg HR) with N C Bjerg (DK) windows you can order new from Ertek (DK) who took over the assets in 1997 when NCB went under. Lovely people, but again you need to sit down, particularly on lead time.
Our frames
The images below show samples of the frames we can have made, in both single and twin channel versions, along with the inner ring bar. All of these are pre-anodised. Anodising is the last stage (before glazing) and is done once all the holes have been drilled (both frame and rings).
Frames are typically made in two (or more if mitre corners) sections, held together with anodised aluminium inserts we call fishplates. These typically have four stainless steel screws for each, two on each side. Where there are two channels there are typically two fishplates.
Black anodising can be an option for shorter sections (<1m), but is significantly more expensive and inevitably will fade in time. Similarly powder coating is an option, but again this is likely to chip in time. Without doubt the best long term finish is anodised bright aluminium (colour).
Still interested in New?
So, if after all the above you still want a quote for new frames, I need the dimensions of either the existing outer frame or the cutout (but state which). I also need and idea of the hull thickness so we can advise whether a single or twin channel section would be best. Next do you want toughened glass or acrylic and do you want CLEAR or GREY tint (others may be available but won't be in stock). Finally do you want inner rings, interscrews and what hole spacing do you prefer (eg 80 or 100mm). Note that if replacing existing frames fitted with glass we may well be able to reuse the glass.
Herzim strip - what?
Just for information, some frames have a channel on the outer surface in line with the fastener holes. This channel has a trapezoidal section. Herzim strip is a PVC strip designed to fit in the channel and cover the fasteners. The strip comes in various widths, normally in black, but sometimes in grey. We don't have access to a new frame section with this, but you may well see this on older frames (particularly on motor boats).
Phew!